The present invention relates generally to golf balls containing a fast-chemical-reaction-produced component formed, in part, from a polyisocyanate copolymer. More particularly, the golf balls contain a fast-chemical-reaction-produced component formed from a reactant, such as a polyol, and an aliphatic/aromatic isocyanate copolymer. Preferably, the copolymer is an isocyanate copolymer of toluene diisocyanate and hexamethylene diisocyanate. The component formed by the fast-chemical-reaction can be utilized to form the core, intermediate layer(s) and/or cover layer(s) of a golf ball. Each of the core, intermediate and/or cover layers may include one or more different layers.
Commercial golf balls today consist generally of three types of configurations. The first type is a multi-piece, wound ball in which a vulcanized rubber thread is wound under tension around a solid or semi-solid core, and thereafter enclosed in a single or multi-layer covering of a tough, protective material. A second type of a golf ball is a one-piece ball formed from a solid mass of resilient material which has been cured to develop the necessary degree of hardness to provide utility. A third type of ball is a multi-piece, non-wound ball that includes a liquid, gel or solid core of one or more layers and a cover having one or more layers formed over the core.
Conventional golf ball covers have been made of ionomer, balata, and slow-reacting, thermoset polyurethane materials. When polyurethane covers are made by conventional methods, such as by casting, a substantial amount of time and energy is required, thus resulting in relatively high cost. In addition, when producing one or more core and/or cover layers from polyurethane, other processing problems occur, including discoloration due to ultra-violet light, slower reaction times, and insufficient physical properties. Although satisfactory in some respects, a need exists for improved polyurethane formulations and methods of producing golf balls and components thereof.
It would be useful to develop a golf ball containing a fast-chemical-reaction-produced component, such as at least one core or cover layer, particularly one which contains polyurethane, polyurea, epoxy and/or unsaturated polyester.
It would also be useful to form a golf ball core, interior, or cover layer from a reaction injection molding system using a suitable cross-linker that provides little or no discoloration due to ultra-violet light, has fast reaction times, and exhibits good physical properties.
It would be particularly desirable to provide a multi-piece golf ball of the third type previously described utilizing the noted fast-chemical-reaction-produced component and/or the noted cross-linker.
Another object of the invention is to provide a method of making a golf ball of the type described above.
The present invention is directed to a method of making a golf ball component by reaction injection molding a polyisocyanate copolymer and at least one reactant. Preferably, the polyisocyanate copolymer is a copolymer of an aromatic isocyanate and an aliphatic isocyanate. Most preferably, the polyisocyanate copolymer is a copolymer of hexamethylene diisocyanate (xe2x80x9cHDIxe2x80x9d) and toluene diisocyanate (xe2x80x9cTDIxe2x80x9d). The golf ball component formed by reaction injection molding can be a core, mantle, or cover layer.
In an additional aspect, the present invention is directed to a method for making a golf ball component. The method comprises mixing a polyisocyanate copolymer and at least one reactant. The polyisocyanate copolymer and at least one reactant are chemically reacted to form a reaction mixture adapted for reaction injection molding. The reaction mixture is then molded to form a golf ball component.
In another aspect, the present invention is directed to a process for forming a golf ball component comprising polyurethane or polyurea by a reaction injection molding technique. The process includes mixing a polyisocyanate copolymer and reactant, such as a polyol, into a closed mold. The polyisocyanate copolymer is a copolymer of toluene diisocyanate and hexamethylene diisocyanate. The polyisocyanate copolymer and reactant are chemically reacted in the closed mold to form a reaction mixture. The reaction is molded in the closed mold to form a golf ball component.
In a further aspect, the present invention is directed to a method for making a polyurethane or polyurea covered golf ball. The method includes mixing a polyisocyanate copolymer, the polyisocyanate copolymer including toluene diisocyanate and hexamethylene diisocyanate, and a reactant such as a polyol. The polyisocyanate copolymer and reactant are chemically reacted to form a reaction mixture adapted for reaction injection molding. The reaction mixture is molded about a core, or a core with one or more intermediate layers, to form a polyurethane or polyurea covered golf ball.
In a still another aspect, the invention is directed to the use of a hexamethylene diisocyanate/toluene diisocyanate copolymer as a cross-linker for a polyurethane/polyurea reaction injection molded golf ball cover or mantle (i.e. intermediate or inner cover layer). The copolymer exhibits good light fastness, speed of reaction and physical properties.
Other objects of the invention will become apparent from the specification, drawings and claims.